Photoshop: Does It Use CPU or GPU?

When it comes to Photoshop, which is more important: the processor or the graphics card? Here’s everything you need to know.

Published Categorized as Apps & How-to's, Photoshop

So you’re wondering if Adobe Photoshop, the ultimate graphics editing app, mainly uses your computer’s processor (CPU) or graphics card (GPU)?

This is a good—and important—question. As a photographer or graphic designer, one of the most important things is to make sure your computer is equipped with the hardware it needs to run Photoshop smoothly.

Photoshop uses both the computer processor and the graphics processor. The CPU provides the circuitry needed to run the program, and the GPU provides the computational power to render images without lagging.

Photoshop is a graphics editing app for raster, or bitmap, images. The images made in or edited with Photoshop consist of pixels within a grid, also called a map of bits.

Raster images are different from vector images, created in and edited with Illustrator, and consisting of mathematical formulas. Vector images can be scaled up or down without loss of visual quality; raster images can’t.

What Raster Graphics Are Made Out Of

As the Encyclopedia Britannica explains, raster images are made up of tiny squares of equal size called pixels. These pixels are arranged in a matrix-like structure consisting of columns and rows.

Each pixel takes on a single color. When displayed on the screen, they form a unique, recognizable graphic. Editing this graphic means adding, changing, or deleting pixels within its boundaries, called the canvas.

The higher the resolution of an image, the more pixels it contains. A 1024 x 768 image, for example, contains 1024 pixel columns and 768 pixel rows, for a total of 786,432 pixels. A Full HD (1980 x 1080) image, on the other hand, has 2,073,600 pixels, and a 4K (3840 x 2160 pixels) has 8,294,400 pixels.

Larger images, made up of more pixels, also require more processing power to render and edit. I have explained the reasons for this—and what they have to do with your machine’s CPU vs. GPU—below.

How Raster Graphics Are Rendered on the Screen

When you create or edit images in Photoshop, the CPU sends information about each pixel to the GPU. The GPU performs calculations on these pixels and stores the results in what’s called Video Random Access Memory (VRAM). This paints a frame, a momentary snapshot of the image—that can then be shown on the screen.

At any moment of time, the GPU stores a multitude of frames in a frame buffer that—as pixels are added to and removed from the image—get continually shown on the screen. Graphics cards are designed to be extremely performant at this rendering task, whereas computer processors aren’t.

You can run Photoshop without a GPU. But your CPU will start to struggle with painting the frames sooner rather than later, and you will start to experience lag. With the CPU busy painting frames, your whole computer will slow down significantly.

“Lag” is another way to say that your processor is having trouble generating enough frames per second (FPS). As a result of the low FPS, the image on the screen is starting to stutter, and the transitions from one frame to another are no longer seamless.

Also, a number of features won’t work if you don’t have a GPU. These features include, among others, 3D, Perspective Warp, and Scrubby Zoom.

Minimum Requirements to Run Photoshop

Although you could use Photoshop on pretty much any macOS or Windows computer with varying degrees of success, it’s best if your system meets the minimum requirements to ensure a good user experience.

According to Adobe, to run Photoshop, your computer must have a 64-bit CPU with a speed of 2 GHz or more, at least 8 GB RAM, and a graphics card with a GPU with at least 4 GB of memory. It’s also recommended to have at least 4 GB of free hard disk space.

The CPU is the most important piece of hardware for a Photoshop workstation, American custom workstation company Puget Systems explains, with the processor’s architecture more important than the number of cores.

Nothing can beat Apple processors on a Mac or MacBook. On a Windows PC, Intel is generally considered the better choice than AMD (even though its lead has been increasingly challenged in recent years).

Photoshop can run on a system with an onboard graphics card. However, big screens and large graphics require a dedicated graphics card with plenty of VRAM for the frame buffer. The general consensus is that NVIDIA cards are better than AMD cards.

Image courtesy of Gorodenkoff /Depositphotos

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